Planes have never been so full. There was barely a spare seat this summer, and the next few months should be the same. To the list of things airlines have taken away — hot meals, blankets, headphones — you can add personal space.

For airlines and the people who invest in them, it makes sense. Because of consolidation, partnerships and a push to eliminate unprofitable routes, airlines can adjust schedules to match demand and charge more.

But customer comfort is an afterthought. Not to mention space in the overhead bin.

"There are some days on some flights when there are simply no physical seats left," says Jim Reichart, vice president of marketing and sales for Frontier, which sold 91 percent of its seats in July and August. Frontier and US Airways both had their best August for percentage of seats filled.

The figures shouldn't come as a surprise to anyone who fought over an armrest this summer. With 130 million people flying, little perks like empty middle seats or flying standby were hard to come by.

Airline executives used to add flights and routes to protect market share. This often meant there were more seats than travelers.

"In the past we had the problem of people operating airlines based on ego," says airline consultant Michael Boyd. "Now they're operating on the basis on how much money they can make."

Overall, 86.4 percent of seats were filled by paying customers in July and August, according to an Associated Press analysis of preliminary data reported by 16 major U.S. airlines. That edges last summer's record of 86.3 percent.

Add in seats occupied by off-duty airline staff, who often fly free, and passengers who redeemed frequent-flier miles, and there was hardly any room this summer.

Analysts say there may be more space this fall, but not much, if the economy slows further. Either way, flights around Thanksgiving and Christmas will be packed. And fuller flights anytime mean you're less likely to get a seat if your flight is canceled.

Airlines generally lose money on empty seats because they are already paying for fuel, pilots and flight attendants. But how many seats are filled is only one factor in airline profitability. Airlines have to make enough money from fares and fees to cover fuel and labor costs.

All the major airlines except American have made money this year. United charged about 8 percent more for each seat in July than last year, and 11 percent more in August.

Until 1978, regulation limited airline competition, allowing them to make money even when planes weren't full. In more recent years, technology has allowed airlines to routinely schedule full flights — and cutthroat competition has forced them to.

In the early 1970s, before airlines were deregulated, about half of seats were sold. In the first decade after deregulation, airlines sold about 60 percent of seats. That number slowly increased over the decades. In 2008, faced with high fuel costs and falling demand in a recession, airlines ended hundreds of money-losing flights.

With the summer travel season over, airlines are cutting seats available in the U.S. by about 2 percent this fall, according to Barclays Capital. Lucrative international flights, which make up a smaller number of airline routes, will increase by 3.5 to 5 percent.

Growth takes back seat

Airlines are putting next year's growth plans on hold, with high fuel prices and a sluggish economy forcing them to focus on flying that will turn a profit. United Continental Holdings Inc. plans to keep flying levels flat next year. Delta Air Lines Inc. is cutting flying. AMR Corp.'s American Airlines is cutting flying more than it had planned for the fourth quarter, too. Those three are biggest U.S. airlines. Delta president Ed Bastian told an analyst conference on Tuesday that demand has remained strong. But he says the airline assumes high fuel prices are here to stay, and it wants to make sure it only flies the routes where demand is strong enough to be profitable.